This invention relates to liquid dispensers, and in particular, those that are useful to automatically terminate the filling cycle when the level of liquid in a receptacle exceeds a predetermined level.
The restaurant and bar industry through the years has required liquid dispensers, wherein the operator, such as a waiter or bartender, places a receptacle into a position to receive a liquid and then dispenses a liquid from a nozzle to a level desired by the operator. In early days the receptacle was placed below the nozzle and a manually actuated lever was pushed away from the operator to open the valve and dispense liquids. Subsequently, a solenoid attached to an electric circuit was used to operate a valve, wherein upon pushing a button to actuate the electric circuit the valve would open and dispense liquid into the receptacle. For soft drink dispensing, it was common to have soda water operative with one valve and syrup operative with another valve wherein both valves would feed a nozzle. By actuating the solenoids through a switch element to open the valves it was possible to dispense carbonated liquid into a receptacle to a level desired by the operator.
Although such prior devices were used primarily for dispensing carbonated liquids, such devices could also be used for dispensing coffee, tea and any other of the beverages commonly offered at restaurants or bars.
In the fast food industry it became desirable to have an automatic filling device. These automatic filling devices took many forms, however, most commonly these automatic filling devices either consisted of a timing circuit attached to the solenoid, whereby the electric circuit was actuated by a switch which would then maintain the solenoid in an actuated state to keep the valve open for a predetermined time. At the expiration of the time the solenoid would de-actuate and close the valve to terminate the filling cycle.
Such prior devices suffered from the problem that when dispensing carbonated liquids, which were commonly served with a certain volume of ice, it was difficult to control the amount of ice placed within the receptacle, consequently a predetermined time period would dispense a predetermined amount of liquid and if ice in excess of a certain amount existed within the receptacle the liquid would overflow the receptacle, thereby creating a wasteful and unsanitary situation.
Other prior devices utilized a volumetric approach, whereby a certain volume of liquid was dispensed into a receptacle at the will of the operator. Such prior devices also suffered from the inherent deficiency that it was difficult to control the amount of ice placed into a receptacle by the operator, consequently by dispensing a certain volume of liquid it often occurred that the volume of liquid would overflow the receptacle because of the amount of ice placed within the receptacle. These prior devices created both an unsightly and unsanitary condition, which long plagued the soft drink or liquid dispensing industry.
Such prior devices also had an inherent deficiency in that different sized receptacles could not be used, because a filling cycle established for a certain period of time or based upon a certain volume of liquid was not adaptable to changes in receptacle size. It was difficult to accurately control the amount of liquid dispensed, and consequently operator attendance was continuously required.
Attempts have been made to solve some of the problems inherent in these prior systems. A probe was suspended from the lower portion of the faucet assembly next to the nozzle, whereby movement of the receptacle toward the probe to contact and rotate the probe would initiate the filling cycle. The filling cycle was then controlled by a probe in contact with the rim of the receptacle. When the fluid/foam over filled the receptacle and contacted the probe the filling cycle was terminated. The drawback to these devices was the fact that the probe actually contacted the cup rim and if a cup was brought back for a refill various viruses could be transferred to the cup lever and thereby to another user.
In the prior device of U.S. Pat. No. 3,916,963 an automatic drink dispenser is shown for filling cups with a liquid when placed into a receiving position on a platform. The automatic drink dispenser includes a solenoid controlled valve for dispensing liquid into cups. A pivotal contact member is positioned below the nozzle so that movement of the cup toward the contact member caused the contact member to pivot about an axis thereby actuating a microswitch. The microswitch is operative to energize an electric circuit and a solenoid to open a valve and initiate dispensing of the liquid. When the liquid reached a predetermined level a sensing member which is suspended below the nozzle and was connected to the contact member is contacted by the liquid or foam as it reaches a predetermined level and overflows the cup. An electrical means interconnecting the sensing member and the solenoid controlled valve closes the valve to stop the flow of liquid.
Although the device of U.S. Pat. No. 3,916,963 was able to solve some of the deficiencies of prior devices other undesirable characteristics appeared. For example, the liquid within the cup would touch the sensing member, and indeed had to touch the sensing member to terminate the filling cycle. Oft times, an individual orders a cup of liquid such as a soft drink and drinks a certain portion of the drink and then asks for a refill. In such cases the same cup is used, although partially filled, and upon refilling liquid placed into the cup would rise to a certain level to touch the sensing member. Consequently, a partially empty cup which had made contact with a person's mouth and contained perhaps some saliva would then be refilled, and the individual's saliva and possibly viruses or bacterial organisms from their mouth would rise with the liquid in the cup during the filling cycle and touch the contact member or sensing member. Consequently, the contact member or sensing member often became contaminated with saliva and viruses or bacterial organisms from individual's mouths. Due to the presence of certain viruses these automatic dispensers have become undesirable to use.
The automatic drink dispenser of U.S. Pat. No. 3,916,963 illustrates another deficiency in that certain liquids, such as root beer, have a tendency to foam a great deal. Consequently, as the foam contacted the sensing member extending downwardly into and toward the cup the valve would shut-off even though the liquid had not reached a sufficient level within the cup. Consequently, the operator would have to remove the cup and thereby pivot the contact member to its original position, and then re-insert the cup to rotate the contact member to actuate the microswitch and again initiate the filling cycle. When using liquids which foamed a great deal this was highly undesirable, because it required considerable movement of the cup into and out of the receiving position, causing additional spillage and seriously degrading the efficiency of the operator.